Across the ancient world, civilizations separated by thousands of miles constructed remarkably similar pyramids, temples and massive stone monuments. Could these shared designs point to a common source of knowledge—and might that source have come from beyond Earth? From the mysterious ruins of Nan Madol and the extraordinary precision of the Great Pyramid to the technological mysteries of Teotihuacan and Stonehenge, investigators examine theories that ancient builders possessed knowledge far beyond what history suggests. Could extraterrestrial visitors have provided humanity with a master blueprint for some of the world's greatest ancient structures? Stay up to date on all of your favorite shows on The HISTORY Channel website at http://history.com/schedule #AncientAliens Subscribe for more from Ancient Aliens and other great The HISTORY Channel shows: http://histv.co/SubscribeHistoryYT Find out more about the show and watch full episodes on our site: https://histv.co/AncientAliens Check out exclusive The HISTORY Channel content: History Newsletter - https://histv.co/newsletter Website - https://histv.co/History Facebook - https://histv.co/Facebook Instagram - https://www.instagram.com/history TikTok - https://www.tiktok.com/@history "Ancient Aliens" explores the controversial theory that extraterrestrials have visited Earth for millions of years. The HISTORY® Channel, a division of A+E Global Media, is the premier destination for historical storytelling. From best-in-class documentary events, to a signature slate of industry leading nonfiction series and premium fact-based scripted programming, The HISTORY® Channel serves as the most trustworthy source of informational entertainment in media. The HISTORY® channel has been named the #1 U.S. TV network in buzz for seven consecutive years by YouGov BrandIndex, and a top favorite TV network by Beta Research Corporation. For a deeper dive, visit history.com or follow @history on Instagram, Twitter, Facebook, YouTube and TikTok.